Design, synthesis, and antibacterial activity of novel Schiff base derivatives of quinazolin-4(3H)-one

Novel imine derivatives of quinazolin-4(3H)-one were designed and synthesized by using aminoethyl moieties to increase the amine bridge of quinazolin-4(3H)-one amine and then introducing various aromatic aldehydes. The target compounds were characterized by proton nuclear magnetic resonance spectroscopy (H-1 NMR), carbon nuclear magnetic resonance spectroscopy (C-13 NMR), mass spectrometry (MS), infrared spectroscopy (IR), elemental analysis, and X-ray diffraction crystallography. Bioassay results indicated that some of the compounds showed good to excellent antibacterial activities against tobacco bacterial wilt and tomato bacterial wilt. The 50% effective concentrations (EC50) of the compounds against tobacco and tomato bacterial wilts ranged from 63.73 mu g/mL to 201.52 mu g/mL and 38.64 mu g/mL to 81.39 mu g/mL, respectively, which are lower than that the positive control thiodiazole copper (216.70 and 99.80 mu g/mL). These results indicated that novel Schiff base derivatives containing the 4(3H)-quinazolinone moiety can effectively control tobacco and tomato bacterial wilts. (c) 2014 Elsevier Masson SAS. All rights reserved.